Don't blame it on the moonlight

This is a very minor thing, but still amusing.

During the battles around Portland in the first two days of June, the Irish Brigade gets off their train at midnight of 1-2 June 1862 and make a moonlight march to get into position.:

As they approached the brook, Steele’s British infantry came under fire from Meagher’s troops, notably Col. John Burke’s 63rd New York Volunteers and Col. Robert Nugent’s 69th New York; they were supported by Lt. Col. Patrick Kelly’s 88th New York and Capt. John D. Frank’s Battery G, 1st New York Light Artillery. The brigade had arrived in Portland at midnight by train, and marched out to the battlefield by moonlight, led by some of the stalwart men of the 3rd Maine Militia and Saunders’ sharpshooters, who had held the British off the previous day.

This should not have been nearly so easy as it is presented, for one simple reason - the moon was four days past new. As such, not only should it have been very dim, but it set an hour and a half before midnight.
This should not, by itself, be the kind of detail that cripples a timeline. But it is not as though this kind of thing is impossible to find out.